COIL STRUCTURE AND ELECTROMAGNETIC COMPONENT USING THE SAME
An electromagnetic component including a multi-layer, spiral coil structure embedded in a molded body is disclosed. Each layer of the coil structure makes approximately one and a quarter turns of a winding. Each layer of the coil structure has a loose middle segment, two slim end segments overlapping each other with a spacing therebetween, and tapered neck segments respectively connecting the loose middle segment with the two slim end segments.
This application is a continuation of U.S. application Ser. No. 13/868,995, filed Apr. 23, 2013, which claims priority from U.S. provisional application No. 61/637,277, filed Apr. 24, 2012.
BACKGROUND OF THE INVENTION1. Field of the Invention
The present invention relates to a coil structure for electromagnetic components and, more particularly, to a coil structure constructed.
2. Description of the Prior Art
As known in the art, electromagnetic components such as inductors or choke coils have typically been constructed by winding conductor wires about a cylindrical core. For example, insulated copper wires may be wrapped around the core. Structures of such electromagnetic components are usually designed to meet the surface mounting technology (SMT) or surface mounting device (SMD).
The rapid advance toward electronic components having smaller size and higher performance in recent years is accompanied by strong demand for coil elements having smaller size and higher performance in terms of saturation current (Isat) and DC resistance (DCR). However, the size of the prior art electromagnetic component is difficult to shrink further.
What is needed, therefore, is an improved electromagnetic component having better performance such as larger saturation current, reduced DCR and better efficiency, while the size of the electromagnetic component can be miniaturized.
SUMMARY OF THE INVENTIONIt is one object of the invention to provide an improved coil structure for electromagnetic components, which can be formed with a smaller size and high yield.
According to one embodiment, an electromagnetic component includes a multi-layer coil structure embedded in a molded body is disclosed. Each layer of the coil structure comprises a loose middle segment, two slim end segments overlapping each other with a spacing therebetween, and tapered neck segments respectively connecting the loose middle segment with the two slim end segments.
According to one aspect of the invention, an electromagnetic component includes a substrate; a multi-layer coil structure on the substrate; and a molded body encapsulating the substrate and the coil structure. The molded body fills into a central opening of the substrate to thereby constitute a pillar surrounded by the coil structure. A coil winding of the coil structure is spirally wound with multiple turns around the pillar. The coil winding of the coil structure comprises multiple segments including two distal, slim end segments, intermediate segments with a uniform width, and tapered segments. At least one of the tapered segments has an outline that conforms to outline of an inner terminal of the coil winding of the coil structure.
These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings.
The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. In the drawings:
It should be noted that all the figures are diagrammatic. Relative dimensions and proportions of parts of the drawings are exaggerated or reduced in size, for the sake of clarity and convenience. The same reference signs are generally used to refer to corresponding or similar features in modified and different embodiments.
DETAILED DESCRIPTIONIn the following description, numerous specific details are given to provide a thorough understanding of the invention. It will, however, be apparent to one skilled in the art that the invention may be practiced without these specific details. Furthermore, some well-known system configurations and process steps are not disclosed in detail, as these should be well-known to those skilled in the art. Therefore, the scope of the invention is not limited by the flowing embodiments and examples.
The substrate 20 may have annular shape that is similar to the annular shape of the coil structure 10a or 10b that is disposed on either side of the substrate 20. A central opening 200 may be defined together by the sidewalls of the substrate 20 and the sidewalls of the coil structures 10a and 10b. The central opening 200 may be formed by using laser or mechanical drill methods after the formation of the coil structures 10a and 10b. According to the embodiment, the substrate 20 may have an irregular side profile, for example, saw-toothed shape, around the perimeter of the central opening 200. It preferable to form less serration 202 around the perimeter of the central opening 200 so that more magnetic material may be filled into the central opening 200 and the performance of the electromagnetic component 1 can be improved.
The electromagnetic component 1 may further comprise a molded body 12 formed in a shape of, for example, rectangular parallelepiped, for encapsulating the coil structures 10a, 10b and the substrate 20. However, it is to be understood that other shapes or profiles of the molded body 12 are also possible. For example,
The molded body 12 may comprise thermosetting resins and metallic powder such as ferrite powder, ion powders, or any suitable magnetic materials known in the art. The molded body 12 also fills into the central opening 200 to form a central pillar 200a that is surrounded by the coil structures 10a and 10b, wherein the central opening 200 and the central pillar 200a may have various shapes or outlines, for example, circular, oval, polygonal or elliptic shapes when views from the above.
According to the embodiment, the electromagnetic component 1 may be manufactured as a surface mount device SMD, which is a device that can be mounted directly to a surface of a circuit board or leadframe. For example, the electromagnetic component 1 may comprise two SMD electrodes 206 and 208 electrically connected to two terminals 106 and 108 of the coil structure 10a or 10b, respectively. For example, the SMD electrodes 206 and 208 may comprise soldered or plated metals.
According to the embodiment, the coil structure 10a or 10b may be a multi-layer winding, wherein each layer of the coil structure makes at least one turn of a winding. For example, each layer of the winding makes approximately one and a quarter turns to form a spiral pattern when viewed from above. For example, as can be seen in
According to the exemplary embodiment, the two slim end segments 104a and 104b may have a narrower line width w2 and w3 both less than or equal to 100 micrometers, for example. The line width w2 may not equal to the line width w3. It is understood that the line widths w1, w2 and w3 are adjustable depending upon the design requirements.
It is noteworthy that the loose middle segment 102, the tapered neck segments 103a and 103b, and the two slim end segments 104a and 104b are all in the same horizontal plane or level, and may be fabricated concurrently in the same process step. When viewed from above, the layer of the coil structure 10a or 10b may have an annular, oval-shaped stripe pattern. The layers of the coil structure 10a or 10b may be insulated from one another using an insulating film (not explicitly shown) interposed therebetween. The adjacent layers of the coil structure 10a or 10b may be electrically connected together in series using a via or plug formed each insulating film. By using such space efficient configuration, the performance of the electromagnetic component 1 can be improved and/or the size of the electromagnetic component 1 can be further reduced.
According to the embodiment of this invention, the coil structure 10a or 10b may be fabricated using the following manufacturing techniques including but not limited to etching, plating, etc. It is to be understood that the process steps are only for illustration purposes, and other methods and manufacturing techniques, for example, printing, may be used in other embodiments.
A patterned photoresist layer 310 is then provided on the surface of the substrate 300. The patterned photoresist layer 310 comprises openings 310a exposing a portion of the copper layer 302. For example, each of the openings 310a has a width of about 210 micrometers and a depth of about 50 micrometers.
As shown in
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According to this embodiment, the coil winding of each of the coil structures 10c, 10d may be spirally wound in the same horizontal plane with multiple turns around the central pillar 200a. As shown in
The spiral coil winding of the coil structure 10c may have multiple segments including but not limited to two distal, slim end segments 304a and 304b, intermediate segments 302 with a uniform width, and tapered segments 303a and 303b. In order to efficiently utilize the space, the tapered segment 303a may have an abrupt edge and an outline that conforms to the outline of the inner terminal A, such that the tapered segment 303a at least partially encompasses the two adjacent sides of the terminal A. Compared to the tapered segment 303a, the tapered segment 303b does not have abrupt edges. As shown in
However, it is to be understood that the annular coil pattern around the central pillar 200a may have various thicknesses or dimensions in other embodiments. For example, as shown in
Those skilled in the art will readily observe that numerous modifications and alterations of the device and method may be made while retaining the teachings of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.
Claims
1. An electromagnetic component, comprising:
- a conductive structure, comprising at least one conductive layer to form a coil, wherein a conductive layer comprises a middle segment, a first slim segment and a second slim segment, wherein the width of the middle segment is respectively greater than that of the first slim segment and the second slim segment, wherein a portion of an outer side surface of the first slim segment and a portion of an inner side surface of the second slim segment are placed side by side for matching the line width of the middle segment with a total of the width of the first slim segment, the width of the second slim segment and a spacing between said two slim segments.
2. The electromagnetic component according to claim 1, wherein the conductive layer further comprises a first transition segment, wherein the width of the first transition segment is gradually reduced to connect the middle segment to a first end point of the first slim segment.
3. The electromagnetic component according to claim 1, wherein the line width of the middle segment is substantially equal to the total of the width of the first slim segment, the width of the second slim segment and the spacing between said two slim segments.
4. The electromagnetic component according to claim 2, wherein the width of the first transition segment is gradually reduced only in an inner side of the first transition segment to connect the middle segment to the first end point of the first slim segment.
5. The electromagnetic component according to claim 2, wherein the conductive layer further comprises a second transition segment, wherein the width of the second transition segment is gradually reduced to connect the middle segment to a first end point of the second slim segment.
6. The electromagnetic component according to claim 1, the line width of middle segment is about 210 micrometers, each of the line width of the first slim segment and the line width of the second slim segment is respectively less than or equal to 100 micrometers and the spacing between the first slim segment and the second slim segment is about 5-30 micrometers.
7. The electromagnetic component according to claim 1, the line width of middle segment is about 210 micrometers, each of the line width of the first slim segment and the line width of the second slim segment is respectively less than or equal to 100 micrometers and the spacing between the first slim segment and the second slim segment is about 5-10 micrometers.
8. The electromagnetic component according to claim 1, wherein the conductive structure is on a substrate, wherein a molding body encapsulates the substrate and the conductive structure, wherein the molded body is extended into an opening of the substrate to form a pillar, wherein the coil is wound around the pillar.
9. The electromagnetic component according to claim 1, wherein a first portion of the conductive structure is on a top surface of the substrate and a second portion of the conductive structure is on a bottom surface of the substrate, wherein a molding body encapsulates the substrate and the conductive structure, wherein the molding body is extended into an opening of the substrate to form a pillar, wherein the coil is wound around the pillar.
10. The electromagnetic component according to claim 8, wherein the substrate has an annular shape.
11. The electromagnetic component according to claim 8, wherein the substrate comprises serrations around a perimeter of the opening.
12. The electromagnetic component according to claim 5, wherein a first electrode is electrically connected to a second end point of the first slim segment and a second electrode is electrically connected to a second end point of the second slim segment.
13. An electromagnetic component, comprising:
- a conductive structure, comprising at least one conductive layer to form a coil, wherein a conductive layer comprises a middle segment, a first transition segment, a second transition segment, a first slim segment and a second slim segment, wherein the width of the middle segment is respectively greater than that of the first slim segment and the second slim segment, wherein a portion of an outer side surface of the first slim segment and a portion of an inner side surface of the second slim segment are placed side by side, wherein the width of the first transition segment is gradually reduced to connect the middle segment to a first end point of the first slim segment, and the width of the second transition segment is gradually reduced to connect the middle segment to a second end point of the first slim segment.
14. The electromagnetic component according to claim 13, wherein a portion of an outer side surface of the first slim segment and a portion of an inner side surface of the second slim segment are placed side by side such that the line width of the middle segment is substantially equal to the total of the width of the first slim segment, the width of the second slim segment and a spacing between the two slim segment.
15. The electromagnetic component according to claim 14, wherein a first electrode is electrically connected to a second end point of the first slim segment and a second electrode is electrically connected to a second end point of the second slim segment.
16. The electromagnetic component according to claim 13, the line width of middle segment is about 210 micrometers, each of the line width of the first slim segment and the line width of the second slim segment is respectively less than or equal to 100 micrometers and the spacing between the first slim segment and the second slim segment is about 5-30 micrometers.
17. The electromagnetic component according to claim 13, the line width of middle segment is about 210 micrometers, each of the line width of the first slim segment and the line width of the second slim segment is respectively less than or equal to 100 micrometers and the spacing between the first slim segment and the second slim segment is about 5-10 micrometers.
18. The electromagnetic component according to claim 13, wherein the conductive structure is disposed on a substrate, wherein a molding body encapsulates the substrate and the conductive structure, wherein an opening is formed inside the coil and penetrating through the substrate; and the magnetic molding body encapsulates the conductive structure and extending into the opening to form a pillar for the coil.
19. The electromagnetic component according to claim 18, wherein a first portion of the magnetic molding body disposed inside the opening is in contact with a portion of the coil on the at least one conductive layer.
20. The electromagnetic component according to claim 18, wherein the width of the first transition segment is gradually reduced only in an inner side of the first transition segment to connect the middle segment to the first end point of the first slim segment.
Type: Application
Filed: Apr 28, 2015
Publication Date: Aug 27, 2015
Patent Grant number: 10121583
Inventors: WEI-CHIEN CHANG (Hsinchu County), CHIA-CHI WU (New Taipei City), LANG-YI CHIANG (Keelung City), TSUNG-CHAN WU (Hsinchu), JIH-HSU YEH (Taipei City)
Application Number: 14/697,645